Slight Shaking around 70mph

[philjw90SHO]

Title says it all

I just got all but one of the tie rod ends and the steering box replaced at les schwab.

It shakes between 70 and 80 mph.

Any ideas?

 

[yamahaSHO]

Tires out of balance?

 

[sdpatt]

Tires out of balance?

A loose suspension or steering component can exacerbate a vibration, but only a dynamic imbalance can create one. A road speed dependent vibration in a car is usually caused by the tire and wheel balance.

 

[Gurt Diggler]

I have the same thing here, and I know my tires are out of balance. Time to pony up and pay for it.... read: "excuse to get better tires."

 

[PROPHET]

A badly worn tire will cause vibration.

 

[yamahaSHO]

If it were to come unbalanced because of that, then yes. Also, if you were to get a knot in a tire from a belt slipping you may feel something, but it would be all the time. I've run tires down to the cords and I've flat spotted tires because of locking the brakes and I never got any vibration. I could feel the flat spots when I would brake and the weight would shift to the front of the car.

 

[spazmoid]

yup i had that same slight vibration when i was on the highway, before i got new tires and the balancing and alignment that comes with them. With any luck, your tires just need balancing.

 

[RonPorter]

Shake at 70 mph is a classic tire balance issue.

 

[PROPHET]

I had run down the inside of a front tire to the cords and it vibrated pretty bad at the speeds you mention.

 

[qiksho]

as others have said start with a good alignment/balance.

If the shake is still there you need to inspect your wheel bearings and c/v shafts.

I have had shakes in the SHO from all three. The bearing failures I have had usually show them selves at different speeds. The c/v usually are the worst under throttle and don't shake as bad once off throttle.

I have found on the SHO's I have owned that unbalanced tires will normally shake the worst between 65-80. Before that speed and after usually don't shake/ or shake much less.

 

[ShadetreeSHOguy]

meh, just drive at 85 . cause i have the same problem w/my 89. just i need to fork the money up for a balance

 

[shoisfast]

same problem until I got all tires balanced and aligned

 

[RonPorter]

One thing to keep i mind is that a bad alignment does not cause wheel shake. That is virtually always balance, although other issues could be bad wheel bearings. If a cv joint is bad enough to shake, you should hear it at lower speeds.

Alignment will cause bad tire wear, weird steering respnse, etc, but not a shake at 70 mph.

 

[qiksho]

One thing to keep i mind is that a bad alignment does not cause wheel shake. That is virtually always balance, although other issues could be bad wheel bearings. If a cv joint is bad enough to shake, you should hear it at lower speeds.

Alignment will cause bad tire wear, weird steering respnse, etc, but not a shake at 70 mph.

Ron,

I have had two bad c/v's cause shaking, neither of them made noise at slower speeds, during turns, etc. how they normaly have failed for me in the past. Both have caused severe vibration on throttle, in straight line in 2-5th gears.

I totally agree, alignment will not cause shake, only symptoms you described.

 

[RonPorter]

yeah, but the 70 mph shake is virtually always tire balance.

 

[Doug Waschenko]

I have the same vibration. Only at 70mph.
Everything is new. New tires, balanced. Wheels checked for being bent and ok, rebuilt drive shafts, new bearings, new struts, new springs, new busings, new ball joints, new alighnment.
Put it all in, shop guaranteed the vibration would go away, bang, guess who's still here.
Because the vibration is only at 70mph, "they can't verify the complaint" because it is an illegal speed.
The vibration isn't in the steering wheel, never was. The dash board vibrates up and down.
I personally think that there is a stabilizer in the dash that has come loose or it is an aerodynamic issue with the nose.
This has been going on for ten years and my solution is not to drive at 70. It clears up by 75.
No one has ever been able to fix this. Other SHO owners have acknowledged similar situation and don't know what it is either.

 

[RonPorter]

I still maintain that a shake specifically at 70 mph will be tire balance virtually every time.

Go to another shop and get them balanced. Preference is for a speciality repair shop that may handle performance make, and especially if the local SCCA-type folks recommend it. Places like this are always good for alignments, also (but that's not your issue here).

Their comment about 70 mph being illegal shows that they don't give a s**t about your problem!!

If you have the same tire-store doofus doing the same incompetent job on the same machine with the same set of tires, why would the results be different? Some tires are just VERY sensitive to balance (like some SHO folks have found with the ContiExtremeContact, for example)

 

[jessemachone]

aftermarket wheels that are not hub - centric with worn adapters could contribute to your problems as well because the wheels are not traveling in a circular motion but in an eliptical motion.
I am getting rid of my borbet type h's for that very reason. :vomit: